The present disclosure relates to a secondary battery protecting circuit and hybrid power source equipment. More particularly, the disclosure relates to a secondary battery protecting circuit for protecting a nonaqueous secondary battery, and hybrid power source equipment including the nonaqueous secondary battery, a solar cell, and the secondary battery protecting circuit.
Since a solar cell can generate an electric power only while a light is radiated to the solar cell, it is difficult to stably drive an electronic apparatus by the solar cell itself. A method in which hybrid power source equipment is configured by combining a solar cell and a secondary battery with each other, and the secondary battery is used as an electric power buffer is known as a method of stably driving an electronic apparatus. With this method, while an amount of electricity used in the electronic apparatus exceeds an electric-generating capacity of the solar cell, the electronic apparatus is driven by using both the solar cell and the secondary battery. On the other hand, when the amount of electricity used in the electronic apparatus fall below the electric-generating capacity of the solar cell, the secondary battery is charged with an excess electric power from the solar cell. Using such hybrid power source equipment results in that there is no necessity for causing a power generating ability of the solar cell to correspond to an amount of maximum power consumption of the electronic apparatus. Thus, it is only necessary to supply an average amount of electric power from the solar cell to the electronic apparatus. This means that a size of a solar cell module can be miniaturized. Thus, a hybrid technology with which both the stable supply of the electric power, and the miniaturization can be realized can be said as a technology which is very effective for the electronic apparatus which is aimed to be miniaturized and portable.
Now, in the hybrid power source equipment, the safety following a rise of a temperature of the secondary battery needs to be sufficiently taken into consideration. The reason for this is because the possibility that the electronic apparatus loaded with the solar cell is positively exposed to the solar light is high. For example, in the case of a car in a midsummer, there is the possibility that the electronic apparatus is left on a dashboard in the hot sun. In addition thereto, there is feared the generation of the damage of the secondary battery following the large and abrupt rise of the temperature of the inside of the electronic apparatus.